Packaging of integrated circuits (ICs) for microwave test equipment requires a number of characteristics: high isolation is required between different functional blocks, low loss RF transmission paths need to be provided, and the final assembly must be low cost. Traditionally, routing of microwave signals has been done in instruments by coaxial cables with SMA connectors on the ends for frequencies below 20 GHz. However, in the last few years, many ICs operating up to 10 GHz have become cheaply available in plastic or ceramic surface mount packages for mounting on PC boards.
It would be convenient to have a packaging scheme that allows inexpensive, low loss, low reflection, high isolation transitions to either PC boards or SMA connectors. Additionally, it would be advantageous to increase the density of DC and RF connections to the outside world over the 5 mm pitch that has been the standard for microcircuits. A multi-chip module packaging system that addresses these issues is desired.